This project seeks to elucidate the mechanisms by which oral sensory and perceptual experience is generated. Since separate measurement of the various aspects of oral experience is fundamental to this effort, the selection and refinement of appropriate psychophysical methods is a primary and continuing project concern. Currently, responses to each of the four basic taste qualities are quantified in terms of (detection) thresholds and judgments of the intensity and pleasantness of taste stimulation at highly, more commonly-encountered levels of strength. Functional variation is important to the understanding of underlying mechanism. Measures of variation in taste perception are obtained through objective evaluation of age-associated and therapeutically induced changes and of oral sensory disturbances ocurring in association with systemic disease, salivary gland dysfunction or as an isolated complaint. Assessments of olfaction and of oral tactual sensitivity are obtained when they can contribute to an understanding of oral sensory function in relation to the complex stimuli encountered in everyday life.